Thread-controlling mechanism for sewing-machines



G. S. GATCHELL.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JULY 1, I9I8- Patented Dec. 7,1920.

6 SHEETS-SHEET Q A from/[K Patented Dec. 7,1920.-

G. S. GATCHELL.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

APPLICATION-FILED JULY 1 1,361,247.

a. S. GATGHE LL. THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JULY 1. 1918.

1,361,247, Patented Dec. 7, 1920.

6 SHEETSSHEET 3- ATTUR/VEK e. s. GATCHE LL. v THREAD CONTROLLING MECHANISM FOR SEWING MACHINES. APPLICATION FILED JULY I, I918.

1,361,247, v Patented Dec. 7, 1920. I

6 SHEETS-SHEET 4.

WITNESSES= INVENTOR ATTORNEY G. S. GATCHELL.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JULY 1, 1918.

1,3 1,247, Patnt-ed Dec. 7,1920.

6 SHEETS-SHEET 5.

G. S'. GATCHELL.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

APPLICATION FILE D JULY 1, I918@ 1,361,247. Patented Dec; 7,1920.

6 SHEETS-SHEET 6-' INVENTOR UNITED STATES PATENT OFFICE.

GEORGE s; GATCHELL, or ROSELLE PARK,

NEW JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

Original application filed August 10, 1917, Serial No. 185,446.

1918. Serial To all whom it may concern:

Be it known that I, GEORGE S. GAToHELL, a citizen of the United States, residing at Roselle Park, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Thread- Controlling Mechanisms for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to thread-controlling mechanism for sewing machines, more particularly of the multi-needle chainstitch type disclosed-in the patent to Molyneux at al., No. 1,266,036 of May 14, 1918, and has for an object the improvement of the thread-controlling mechanism of the machine disclosed therein to overcome the noise and speed-limitation incident to the use of cam-actuated and spring-controlled thread-engaging levers, and to prevent skipping of stitches or thread-breakage due to abnormal displacement or bunching of the needledoops on-the looper, thereby rendering the machine quiet, smooth-running, and eflicient under high-speed operating conditions.

A further object of the invention is to provide a machine with an improved and simplified covering-thread controlling mechanism.

F urtherobjects of the invention will appear from the following description and claims. 7 v

The present improvements are preferably embodied in a four-needle single-looper machine of the cylinder-bed type adapted to produce a seam such as disclosed in the patent to Munsing No. 506,524, October 10, 1893; an additional needle being added in the present instance, to form an additional row of, stitches. The needle-thread controlling mechanism includes a series of thread-cams adapted to act on the needlethreads directly, thereby securing a posi tive action upon the needle-threads and avoiding the noise and sluggishness of operation incident to the use of cam-operated thread-arms. In the present instance the thread-cams are specially shapedto closely and differentially control the needle-threads,

Specification of Letters lPatent.

Patented Dec. 7, 1920.

Divided and this application fil ed July 1, No. 242,702.

as will be hereinafter explained, to meet the exacting thread-control requirements of a multiple needle single-looper machine of the present character.

The covering-thread controlling mechanism comprises a thread-controlling cam, a pull-off cam and a nipper mechanism acting between the two, the timing being such that a measured quantity of slack covering thread is paid out to the covering-thread fingers at the proper times for incorporation in the stitching. The covering-thread cams are preferably mpunted upon a shaft which carries the needle-thread controlling cams.

In the accompanying drawings Figure 1 1s a right-side elevation of the machine partly in section. Fig. 2 is a similar view from the left-side of the machine. Fig. 3 is a front elevation of the machine with the looper-inclosing end-cap in section. Fig. 3 is a detail elevation showing how the stripper-plates of the take-up mechanism are mounted. Fig. 4 is a rear end elevation of the machine partly in section and with the rear cover-plate removedto expose the mechanism housed within the standard.

F'g. 4 is a detail sectional "icw of the ten slon releasing mechanism. Fig. 5 is an enlarged top plan view of the forward end of the bracket-arm showing the thread controlling mechanism supported thereby. Fig. '6 is an enlarged plan View of the free end portion of the work-arm. Fig. 7 is a perspective view of a detail of the looperactuating mechanism. Fig. 8 is a vertical longitudinal section through the take-up supporting frame. ,Fig. 9 is a plan view of the mechanism carried by the bracket arm adjacent the'stitchi'ng point-.Fig. 10 is a perspective view of the same, with the- Work inposition. Fig.11 is a vertical-sec- 'tion taken in a plane passing through the axis of the lower section of the presser-bar shown in Fig. 10. Figs. 12 and 13 are perspective views of the "mechanism at the 'under side of the throat-plate showing the cooperation of the looper and needle-loop detainer. Fig. 14 is a top plan view illustrating the cooperative relation of the needles, looper, needle-loops and needle-loop detainers. Fig. 15 is a vertical longitudinal section on the line 15-15, Fig. 14, .with the throat-plate and material added. Fig. 16

. the flanged rearward extremity of the tubu- I in cross-section.

lar work-supporting arm 5. which is formed with two angularly arranged fiat sides 6, 7, Fig. 3, and a curved upper side 8, whereby said work-arm is substantially sector-shaped Secured to the front or free end of the work-arm casting is the throat-plate 9 whose opposite lateral edges are grooved at 10 to slidably receive and support the end cap 11 which is sectorshaped at its rearward end to conform to the cross-sectional shape of the work-arm. The under surface of the end cap tapers upwardly and the sides thereof taper forwardly toward the free end of the throatplate, as shown in Figs. 2 and 6, to facilitate the advance of tubular work about the work-arm and toward the stitch-forming mechanism. Journaled in and crosswise of the standard 2, above the horizontal plane of the work-arm and crosswise of the vertical plane of the work-arm, is the main-shaft 12 carrying a pulley wheel 13 and handwheel 14 both cast integral with a common hub 15. i

' The main-shaft is formed with a ballcrank 16 which is embraced by the lower strapped end of a pitman 17 the upper strapped end of which embraces a ballended crank-pin 18 carried by the crank arm 18 at the rear end of the needle-actuating rock-shaft 19 which is journaled Within the bracket-arm 3 and, at its forward end, carries a crank-arm 20 connected to the reciprocating needle-bar 21 by means of the link 22. Secured to the lower end of the needle-bar 21 is the needle-clamp-block 2-3 which, in the present instance, is socketed to receive four needles n 12?, n and n arranged in a vertical plane transversely of the work-arm 5. I

Mounted Within the end cap 11, in cooperative relation with the needles, is the thread-carrying looper 24; the. upper edge of the blade of which is curved concentrically with the curvedupper side of the work-arm, Fig; 3, while the lower edge 24' of said blade is but slightly curved or may even be substantially straight throughout a -ing plane. .The looper-support is clamped main-shaft 12 which imparts loop-seizing portion of its length. The slotted shank of the looper is secured to the looper-support 25 by'a screw 26 permitting adjustment of the looper-blade toward and from the stitchto the front end of the oscillating and endwise movable looper-shaft 27 which is journaled within and lengthwise of the workarm 5 as closely as practicable to the apex of the angle formed by the flat-sides 6 and 7 thereof, Fig. 3, said angle being large enough to accommodate the necessary loopseizing and -shedding strokes of the looper.

It will be seen by referring to Fig. 3 that the needle-eyes are arranged on an incline; being placed at progressively lower elevations beginning with the needle n to compensate for the upward movement of the needles as the looper-beak advances across the space between said needles; the purpose 85 being to insure the passage of the looperbeak at the correct distance above each needle-eye to insure seizure of the respective needle-loop. It will be further seen that the needle points are arranged substantially in a common plane parallel to the plane of the throat-plate; the purpose being to insure that the previously formed needle-loops on the looper will be passed simultaneously by their respective needles at the time the lower edge 24 of the looper-blade occupies a substantially horizontal or otherwise favorable angular position relatively to the throat plate.

The looper-shaft 27 carries at its rearward end a crank-arm 28 having a ballcrank-pin 29 which is embraced by the lower strapped end of a link 30 the upper strapped end of which embraces a ball-eccentric 31 on the and .-shedding movements to the looper. The hub of the crank-arm 28 is formed with a rearward extension carrying a ball-ended pin 28' disposed concentrically with the axis of the looper-shaft and embraced by the 1 socketed end of a link 32 whose opposite end is connected to the depending arm 33 of a rock-lever fulcrumed to oscillate upon and independently of the cross-shaft 34 journaled in the standard 2. The upwardly extending arm 35 of said rock-lever is slotted .at 36 to receive an adjustable pin 37 which, through the pitman 38, connects said lever with the eccentric 39 carried by the mainshaft; said eccentric serving to impart side- 2 wise or needle-avoiding movements-to the 100 or. p

he machine is equipped with differential feeding mechanism comprising main and auxiliary feed-dogs 40 and 41, respectively, actuated through suitable connections with. the main-shaft, such as shown in my said copending application.

The feed-dogs cooperate with a presserfoot comprising, in the present instance, a

. of the presser-bar 45 which is formed in two parallel sections offset from one another and connected to move as one bar by means of the lateral arm 46. The lower section of the presser bar-is journaled in the bushing 47 and bearing lug 48, Fig. 1, and the upper section is journaled in alined bearings formed in the bearing lug 48, Fig. 3, and in the top of the head 4. The presser-bar carries a bracket 49 extending laterally through a slot 50 in'the head 4 and acted upon by a leaf spring 51 the pressure of which may be adjusted by means of the screw 52. The presser-foot may be lifted by means ofthe usual treadle-controlled lever 53 the forward extremity of which extends under the bracket 49. The solepiece of the presser-foot is formed with forwardly extending spaced toes 54, Figs. 9 and '10, defining a slot within which the upturned portions of material to be trimmed pass toward the stitching point.

The machine is provided with trimming mechanism comprising, in the presentinstance, ledger and cutter-blades 55 and 56, respectively, which operate in advance of the stitch-forming mechanism to shear off the upturned portions of material. The ledger-blade rests in a groove 57 in the up per side of the left-hand presser-foot toe 54 and is rigidly clamped to the lower end of a vertically slidable rod 58 journaled in spacedlugs 59 formed on the bracket 60 se cured to and depending from the side of the head 4. The trimmer-actuating mechanism is more fully described in my said copending application.

The covering threads to be incorporated in the upper side of the seam are. presented by a pair of eyed thread-fingers having curved horizontally disposed blades 61, Figs. 9 and 10, and vertically arranged shanks 62; the latter being secured in socketed bosses 63 at the free ends of the thread-finger carryinglevers 64 the opposite apertured ends of which are fulcrumed upon the lower reduced end of the bushingor sleeve 47 surrounding the presser-bar, as-

shown in Fig. 11;" Thethread-finger blades are preferably curved to the same radius concentrically with the presser-bar and operate in planes one slightly abovethe other. ments in oppositeidirections are imparted to the levers 64 by means,of the links 65 which. connect the latter with one arm of the bellcrank-lever 66' fulcrumed .on the headed pin 67 carried iby: the head 4. The other arm of the bellcranklever carries a ball-ended pin 68, which is connected by a link 69 to a ball-ended pin 70 carried by the lower end of the depending arm 71' clamped to the front end of the rpck-shaft Simultaneous oscillatory move- A back-and-forth across the line of seam in front of the needles at one-half the frequency of reciprocation of the needles, so that each threaded-finger presentsits thread to the needles alternately at opposite sidesof the line of seam.

The take-up for the needle-threads consists of a thread-guiding bracket 81 secured to the top of the needle-bar 21- and formed with a horizontal bar having individual needle-thread eyes 82. Coiiperating with the take-up bracket 81 to differentially control the needle threads 19, F, t and t are the respective thread-engaging cams c c 0 and'c, each of which comprises, in the present instance, two similar spaced disks formed integral with a common hub. Said cams are mounted on a cam-shaft 83 which is journaled in a thread-controller frame 84 detachably secured to the top of the bracketarm by screws 84* and is driven by a one to-one bevel-gear connection 85 with the upper end of an inclined shaft 86 inclosed within the shaft casing 87. Theloweriend of the'shaft 86 is connected to the countershaft 78 by a one-to-two speed multiplying bevel-gear connection 88, whereby the shaft 83 is driven at the same speed as the mainshaft 12. Rising from the frame 84 are two standards 89, Figs. 1', 2 and 5, to each of which are pivoted the shanks of two similar fork-shaped thread-guides 90, the tines of each fork beingdisposed at opposite sides of a corresponding one of said thread-cams and apertured at 91 to guide the thread across the active peripheral portion of said cam. Threaded into the shank of each thread-guiding fork 90 is an adjusting screw 92 which determines the position or height of the thread-eyes 91. A spring 93 presses against the inclined rear end of the shank 'of each fork and yieldingly maintains the screw 92 in contact withthe top-surface of the standard 89. One of the tines of each fork 90 is. extended forwardly to form a finger-piece 94 which may be readily lifted by the operator to shift the fork .to threading position, shown in dotted lines, Fig. 1. Disposed in a plane between the spaced members of each thread-cam is a corresponding stripper-plate 95 the upper extremity of which is slotted at 96 to guide the thread and to cause said cam to deflect the thread radially,

thereby overcoming the tendency of the cam to carry the thread around with it. The shanks 97 of the stripper-plates. 95 are fitted in corresponding slots cut in the supporting block or frame 98 and defining spaced and opposed ab'utments 99 against which the shanks 97 are clamped by means of thearched springs 100 through the centers of which'pass the screws 101; said screws serving to slightly flatten the springs 100 and thereby clamp the shanks of the stripperplates 95 tightly against the abutments 99, as will be readilyunderstood.

Co iiperating with the thread-cams are a series of thread-nippers 1", one for each thread. As these nippers are all alike a description of one will suffice. Referring to Fig. 8 it will be seen that each threadnipper comprises a sleeve 102 which is fixed in a socket in an upward extension 103 on the thread-controller frame 84. Fixed within the sleeve 102 is the shank of a headed pin 104 which nips and locks the thread against the top of said 'sleeve 102 under the influence of the relatively strong coiled.

spring 105. The spring 105 surrounds the pin 104 and reacts against a shoulder within the sleeve 102 and an opposedshoulder within a smaller sleeve 106 telescopingwithin the sleeve 102 and sustainedby a cross-pin 107 extending through the pin 104. Jour naled in the frame 84 at the lower ends of the pins 104 is a rock-shaft .108 which is cut away under each of said 'pinsto afford a lifting shoulder 109; The rock-shaft 108 carries a crank-arm 110, Fig. 1, which is pivotally connected to-a pitman 111 actuated by the eccentric 112 on the shaft 83.

The thread-nippers 1' act to lock and release the needle-threads during each cycle of operations, as will be more fully explained.

In addition tothe needle-thread cams, theshaft 83 carries a covering thread-controller cam c and a covering thread pullofi cam 0. These cams and their cooperative thread-guides and stripper-plates are substantially of the same construction as the g0 needle-thread cams and need no further description. A plurality of superposed threadnipper springs 113 are disposed between the thread-cams c and 0 and are actuated in the usual manner by the cam 114 on the shaft 83 to nip the covering threads during the action of the pull-off cams a.

A series of arched ard-members or springs'115 are provide to prevent winding of the needle-thread about the take-up shaft 83 in case of thread-breakage Each of the guard-springs is wide enough to ex tend across the space between the cams for adjacent needle-threads and the ends of said springs may be sprung into suitable recesses provided therefor in the frame 84, as shown in Fig. 8.

Mounted on top of the bracket-arm at the rear of the machine is a tension-supporting frame 116 carrying a series of tensions 117 for the needle, looper and covering threads. Each of these tensions includes a tension-releasing pin 118 being of the well known construction disclosed, for example, in the patent to De Voe, No. 1,146,405. In the present instance, however, the pins 118 are lifted to release the tensions by shoulders 119 afforded by notches in the tensionreleasing rock-shafts 120 journaled in the frame 116. One of the rock-shafts 120 carries an arm 121 having a lateral pin 122 embraced by the forked extremity 123 of a lever 124 secured to the other rock-shaft 120 and actuated by means of a link connection 125 with the presser-foot lifting lever 53. When the presser-foot is'lifted all the tensions 117 will, accordingly, be released.

The thread-engaglng cams carried by the ,thread below the needle-eyes and maintaining the previous needle-loops snugly about the looper-blade.

The eye of the needle n enters the work as the thread-nippers 1' act to lock the needle-threads and as the peak a of cam'c passes the .line of stationary thread-guides 91. The inward inclination ofcam 0* following the peak u gives up the thread required by the eye of needle n as it doubles its thread below the material. Similarly, at successively later stages, the peaks 11, of and M of the cams c 0 and 0 respectively, pass the guides 91 as the eyes of needles 11. n and m respectively, descend below the work, and the inward inclines following said peaks give up the thread required by the res ctive needle-eyes as they double their thread below the work.

At the point '0 the previously formed loop of the needle n is shed from the looper and the outward incline following the point 1'0 and leading to the peak to acts posiing said last-mentioned peaks give up the thread required by the needles to complete their down-strokes, while maintaining the previous needle-threads somewhat taut and closely under control.

When the needles reach the end of their down-stroke the cams have rotated 180 and the slight inward inclination of the cam 0 following this point slightly slackens the thread It so that the loop thrown out by the needle n will not be robbed of any 'of its thread or reduced in size by the contracting tendency of the thread when relieved of strain. The progressivelysteeper outward inclines of the cams 0 c and 0, following the 180"point, act to reduce the sizes of the respective loops presented by the needles M, n and n, by drawing thread back through the eyes of said needles, to reduce said loops to the proper size prior to their' seizure by the looper-beak. It will be understood that since the eye of the needle 01% descends below the work a greater distance than the needle 11 &c., more thread will have to be drawn back through the eye of the needle n than through the eye of the needle 7?, etc., prior to seizure of the needleloops on the looper, in order that said loops may be reduced to substantially the same size. The nippers 1' are opened as the needles start to rise.

When the peak at reaches the line of thread-guides 91, the looper-beak will just have entered the loop of the needle n and the inward inclination of the cam c, fol lowing the peak as, will give up just enough thread to compensate for the take-up action of the needle-bar and maintain the loop of needle n snugly about the looper-blade. Similarly, as the peaks 00 and x pass the guides 91 at successively later stages, the looper will have successively seized the loops of the respective needles 41 n and a and the inward inclines following said peaks will give up just enough thread to compensate for the take-up action of the rising needle-bar and maintain the loops of said needles snugly about the looper-blade.

After the cams have rotated about 325 the last mentioned giving up action of the cams ceases and the continued upward movement of the needle-bar guides 82 acts to draw or meausre from the supply the amount of thread required for the next stitch; the nippers r being still open.

By these means the needle-threads. are controlled in a positive and efficient manner and a high-speed quiet running and quick acting system of dilferential threadcontrollers is provided, thus insuring a full realization of the important advantages inherent in the idea of controlling the needlethreads differentially as disclosed in said Molyneux et al. patent.

By the use of a long radius looper in conjunction with the present thread-controlling mechanism, the needle-loops on the looper will ordinarily be maintained evenly spaced apart so that each needle [in its descent will pass down beside its respective previously formed loop, However, to further insure against abnormal displacement of the needle-loops on the looper, the machine may, if desired, be equipped with the loop-detainers comprising, in the present instance, three hooked fingers 126 for cooperation with the loops of the needles 113,115 and n and an additional oppositely hooked fin er 127 for cooperation with the loop of t e needle n. The detainers 126 are formed at the end of a plate 128, the slotted shank of which is entered by a screw 129 securing the shank of said plate within a groove 130 at the under side of the throat-plate, there'- by permitting adjustment of said fingers curved or inclined opposite to the direction of retraction of the looper and are positioned between the needle-paths and above the looper-path to engage the upper limbs of the respective previously formed needleloops extending between the last stitch and the curved upper edge of the looper-blade, as shown in Figs. 15 and 16 and prevent the retracting looper from dragging said loops back into the paths of their respective next adjacent needles. In practice, it is found that there'is a tendency for the previously formed loop of the needle n to slip toward the point of the looper and into the path of said needle. To avoid this difiiculty, the looper-blade may be notched to provide a shoulder 131 adaptedto engage the loop of said needle n during the first part of the retracting stroke of the looper, as shown in Fig. 12, and drag said loop backwardly a slight distance past said finger 127, the looper at .the same time also moving sidewise under said finger, whereupon the loop slips over the shoulder 131 and is detained at one side of the path of the needle n by said finger, as shown in Figs. 14 and 15. The

tip end of'the finger 127 is preferably curved or directed slightly toward the direction of retraction of the looper-blade and is made shaft 78 by a gear 134 of one-half the size of the gear 80 in order that the shaft 133 will be driven atthe same speed as the main-shaft 12. Mounted upon the shaft 133 and within the Work-arm is a looperthread controller-cam 135, a looper-thread pull-off cam 136 and a thread-nipper actuating cam 137. v v

The construction of the cams 13.5 and 136 is similar to that of the cams carried by the shaft 83; the cam135 being shaped to conacted upon by springs 145 to yieldingly maintain the screws 144 in contact with the brackets 142 while permitting the forks to be swung upwardly to threading position. Stripper Wires 146, corresponding in func tion to the stripper-plates 95 previously described, are situated between the disks of each cam. The nipper-cam 137 acts upon a pair of superposednipper-springs 147 to nip the looper-thread; the timing in the present instance being such that the nippers are closed upon the thread as the looper begins its retracting stroke, and are opened as soon as the advancing looper has entered all of the needle-loops. The pull-off cam 136 begins to pull looper-thread from the supply as soon as the nippers 147 are closed and gives up the thread to theuadvancing looper as soon as the nippers are opened.

It will be apparent to those skilled in the art that the construction shown and described as a specific embodiment of the invention is susceptible of material modification'both in the form and arrangement of the various parts within the scope of the invention.

. Having thus set forth the nature of the invention, what I claim herein is 1. A sewing machine having a plurality of needles set in a plane crossing the line of feed, a single looper cooperating. therewith to form stitches, and thread-controlling mechanism including a plur ality of rotary needle-thread controlling cams acting directly upon their respective needle-threads, and being-relatively timed topositively tighten'the needle-loops successively as they are shed from the looper.

2. A sewing machine having a plurality of needles set in a plane crossing the line of feed, a single looper coiiperating therewith to form stitches, and thread-controlling mechanism including a plurality-of rotary needle-thread controlling cams each .formed with an outward incline leadin said cams being so timed relatively to one to a peak, 1

another and to the looperthat said outward inclines act successively and directly upon the respective needle-threads to tighten the needle-loops successively as they are shed from the looper.

3. A sewing machine having a plurality of needles set in a plane crossing the line of feed, a single looper cooperating therewith to form stitches, and thread-controlling mechanism including a plurality of rotary needle-thread controlling cams acting directly upon their respective needle-thread and being relatively timed to positively tighten the needle loops successively as they are she-d from the looper, and a plurality of thread nippers adapted to look their respective needle-threads during the positive looptightening action of said cams.

' 4. A sewing machine having a plurality A of needles set ina plane crossing the line of feed, a single loop.ercooperating therewith to form-stitches, and thread-controlling mechanism including a plurality of rotary needle-thread controlling cams each formedwith an outward incline leading to a peak, said cams being so timed relatively to one another and to the looper that said inclines act successively and directly upon the respective:needle-threads to tighten the needle-loops successively as they are shed from thelooper, and a plurality of threadnippers adapted to look [their respective needle-threads during the positive loop tightening action of said cams.

5. A sewing machine having a plurality of needles set in a plane crossing the line of feed, a single looper cooperating therewith to form stitches and thread-controlling mechanism including a plurality of rotary needlethread controlling cams'acting directly upon their respective needle-threads and timed as their eyes descend below the work, and to positively tighten the needle-loops successively as they are shed from the looper.

6. A sewing machine having a plurality of needles set ina plane crossing the line of feed, a single looper-cooperating therewith to form stitches, and thread-engaging cams for the needle thre'ads, each constructed to act independently of the other cam or cams to give up threadto its respective needle as the eye thereof descends below the work and to positively tighten its'respective needlethread loop as soon as it is shed from the retracting looper, said cams being further shaped to give up the thread required by the needles-to complete theirw'down strokes.

7. A sewing machine *havingya plurality of needles'set-in a plane crossing the line of feed with the eyes of the needlesfat different elevations, a single looper cooperat ing therewith to form stitches, and a plu rality of needle-thread engaging cams hav- 1 tighten the respectiveneedle-loops as they are shed from the looper.

8. In a sewing machine, in combination, a frame including a bracket-arm, multi-needle single-looper stitch-forming mechanism incorporated insaid frame, and needle-thread controlling mechanism including a plurallty 'of differentially acting threadcams, each for a corresponding one of said needlethreads, said thread-cams being mounted on said bracket-arm to turn about a common axis and thread-guiding means disposed at opposite sides of a the planes of said cams and adapted to guide the needle-threads across the paths of the active peripheral portions of their respective cams.

9; A sewing machine having a pluralityv of needles, a single looper cooperatin therewith to form stitches, means for tig tening the needle loops successively as they are shed from the looper, and a plurality of needle thread nipping devices on the supply side;

of the loop tightening means for locking the needle-threads while the needle-loops are being successively tightened.

10. In a sewing machine, in combination, a frame including a bracket-arm, multineedle single-looper stitch-forming mechanism incorporated in said frame, and'needlethread controlling mechanism including a plurality of thread-cams, each for a corresponding one of said needle-threads, a camshaft common to said thread-cams, a plurality of threadnippers and actuating connections between said cam-shaft and said thread nippers for actuating the latter to nip and release the needle-threads at predetermined times during the stitching cycle.

11. In a sewing machine, in combination, a frame including a bracket-arm, multineedlecsingle-looper stitch-forming mechanism incorporated in said frame, and needlethread controlling mechanism including a supplemental frame detachably mounted on top of said bracket-arm, a plurality of thread-cams, each for a corresponding one of said needle-threads, a cam-shaft common to said thread-cams, a plurality of threadnippers mounted on said supplemental frame and actuating connections between said cam-shaft and said thread-nippers for actuating the latter to nip and release the needle threads at predetermined times during the stitching cycle.

12. In a sewing machine, in combination, a frame including a bracket-arm, multineedle single-looper stitch-forming mechanism incorporated in said frame,'and needleth'read controlling mechanism including a combination, multi needle stitchforming rotary cam-shaft and an oscillatory thread- -nipper* actuating shaft both journaled on mechanism, covering thread laying means, and thead-controlling mechanism for the needle and covering threads comprising a plurality of needle-thread controlling cams,

a covering thread controlling cam, a covering thread pull-olf cam, a shaft carrying all of said cams andmeans connected with the stitch-forming mechanism for rotating said shaft. t

15. A sewing machine comprising, in combination, multi-needle stitch-forming mechanism, covering "thread laying means, and thread-controlling mechanism for the needle and coveringthreadsincluding a covering thread pull-off cam, a covering thread controlling cam, a thread-n'ipperadapted to nip the thread between said cams, a plurality of needle-thread controlling cams, a shaft carrying all of said cams, means carried by said 7 shaft for actuating said thread-nipper and means connected with the stitch-forming mechanism for rotating said shaft.

' 16. A thread-controlling device for sewing machines comprising a frame formed with a slot having a side 'wall defining an abutment, a thread-engaging cam, a stripper-plate cooperating -w1th said cam and with said cam and, having a shank received.

in said slot, and an arched spring for clamping the shank of said plate against said abutment.

18. A thread-controlling device for sewing machines comprising, a frame formed with spaced slots defining. opposed abutments, a pair of thread-engaging cams, a pair of stripper-plates cooperating with said cams and having. shank-portions received in said slots, an arched spring disposed between said shanks, and means for flattening saidspring to clamp the shankportions of said plates against said abutments.

19. In a multiple needle sewing machine,

in combination, a shaft, a plurality of thread-controlling cams carried by said shaft, one for each needle-thread and one or more stationary arched guards disposed between the cams for adjacent needlethreads and partially surrounding said shaft, whereby accidental winding of a broken needle-thread about said shaft is prevented.

20. In a sewing machine, in combination, a frame, a shaft journaled therein, a plurality of thread-controlling cams carried by said shaft, and one or more resilient bowed guard-strips disposed between said cams and partially surrounding said shaft, said frame being formed with portions into engagement with which the terminal portions of said resilient bowed guard-strips are yieldingly held to retain the latter in position.

21. In a sewing machine, in combination, stitch-forming mechanism including a plurality of needles, a main-shaft, a countershaft, a needle-thread controller, shaft, covering thread mechanism including an eyed thread-finger adapted to move back-andforth in advance of the needles and connected to said counter-shaft, a two-to-one speed-reducing driving connection between said mainand counter-shafts and a 0neto-two speed-multiplying driving connecrality of needles, a mainshaft, a countershaft, a looper-thread-controller shaft, cov-' ering thread mechanism includin an eyed thread-finger adapted to move Imok-andforth in advance of the needles and connected to said counter-shaft, a two-to-one speed-reducing driving connection between said mainand counter-shafts, and a oneto-two speed-multiplying driving connection between said counter and looperthread-controlling shafts.

23. In a sewing machine, in combination, stitch-forming mechanism including a plurality of needles, a main-shaft, a countershaft, needle and looper thread-controller shafts, covering thread mechanism including an eyed thread-finger adapted to move back-and-forth in advance of the needles, a two-to-one speed-reducing driving connection between said mainandcountershafts, and a one-to-two, speed-multiplying driving connection between said countershaft and said needleand looper-threadcontrolling-shafts.

In testimony whereof I have signed my name to this specification.

' GEORGE S. GATC'I-IELL. 

